A preamplifier is an integrated circuit used in a disk drive assembly to condition and process data which are retrieved from and stored on a magnetic storage medium, such as a magnetic disk. "Read" circuits in the preamplifier amplify magnetic signals sensed (retrieved) by a read head flying over the magnetic disk. "Write" circuits in the preamplifier apply signals (current pulses) to a write head to be stored as magnetic signals on the disk.
An example of current pulses applied to a write head by a write circuit is shown in FIG. 1. The current creates a magnetic field which is typically stored on a disk. As the frequency of the current pulses is increased, so is the density of the stored data. Since it is desirable to increase the density of stored data, it is likewise desirable to increase the frequency of the current pulses. The time required for the current to change from its present value to its next value (rise and fall times 10A-10B) ultimately limits the frequency of the pulses, therefore it is desirable to reduce the rise and fall times 10A-10B. Accordingly, if the rise/fall speed of the current applied to the write head increases, the writing speed increases.
It would be desirable to improve the rise/fall speed of the current being applied to the write head in order to increase the speed at which the write head can write data into the magnetic mass storage memory. The present invention addresses such a need.